Role of gap junctions in spontaneous activity of the rat bladder

Increased gap junction expression in lamina propria myofibroblasts and urothelial cells may be involved in detrusor overactivity, leading to incontinence. Immunohistochemistry was used to compare connexin (Cx) 26, 43, and 45 expression in the bladders of neonatal, adult, and spinal cord-transected rats, while optical imaging was used to map the spread of spontaneous activity and the effects of gap junction blockade. Female adult Sprague-Dawley rats were deeply anesthetized, a laminectomy was performed, and the spinal cord was transected (T8/T9). After 14 days, their bladders and those of age-matched adults (4 mo old) and neonates (7-21 day old) were excised and studied immunohistochemically using frozen sections or optically using whole bladders stained with voltage- and Ca(2+)-sensitive dyes. The expression of Cx26 was localized to the urothelium, Cx43 to the lamina propria myofibroblasts, and Cx45 to the detrusor smooth muscle. While the expression of Cx45 was comparable in all bladders, the expression of Cx43 and Cx26 was increased in neonate and transected animals. In the bladders of adults, spontaneous activity was initiated at multiple sites, resulting in a lack of coordination. Alternatively, in neonate and transected animals spontaneous activity was initiated at a focal site near the dome and spread in a coordinated fashion throughout the bladder. Gap junction blockade (18beta-glycyrrhetinic acid, 1 microM) abolished this coordinated activity but had no effect on the uncoordinated activity in adult bladders. These data suggest that coordinated spontaneous activity requires gap junction upregulation in urothelial cells and lamina propria myofibroblasts.

Origin of spontaneous activity in neonatal and adult rat bladders and its enhancement by stretch and muscarinic agonists

This study examined the origin of spontaneous activity in neonatal and adult rat bladders and the effect of stretch and muscarinic agonists and antagonists on spontaneous activity. Rats were anesthetized and their bladders were excised, cannulated, and loaded with voltage- and Ca(2+)-sensitive dyes. Intracellular Ca(2+) and membrane potential transients were mapped using photodiode arrays in whole bladders, bladder sheets, or cross-section preparations at 37 degrees C. Intravesical pressure was recorded from whole bladders. In neonatal bladders and sheets, spontaneous Ca(2+) and electrical signals arose at a site near the dome and spread in a coordinated manner throughout the bladder with different dome-to-neck conduction velocities (Ca(2+): 3.7 +/- 0.4 mm/s; membrane potential: 46.2 +/- 3.1 mm/s). In whole bladders, optical signals were associated with spontaneous contractions (10-20 cmH(2)O). By contrast, in adult bladders spontaneous Ca(2+) and electrical activity was uncoordinated, originating at multiple sites and was associated with smaller (2-5 cmH(2)O) contractions. Spontaneous contractions and optical signals were insensitive to tetrodotoxin (2 muM) but were blocked by nifedipine (10 muM). Stretch or low carbachol concentrations (50 nM) applied to neonatal whole bladders enhanced the amplitude (to 20-35 cmH(2)O) of spontaneous activity, which was blocked by atropine. Bladder cross sections revealed that Ca(2+) and membrane potential transients produced by stretch or carbachol began near the urothelial-suburothelial interface and then spread to the detrusor. In conclusion, spontaneous activity in neonatal bladders, unlike activity in adult bladders, is highly organized, originating in the urothelium-suburothelium near the dome. Activity is enhanced by stretch or carbachol and this enhancement is blocked by atropine. It is hypothesized that acetylcholine is released from the urothelium during bladder filling to enhance spontaneous activity.

Symposium Report on Urothelial Dysfunction: Pathophysiology and Novel Therapies

PURPOSE

The basic premise of this symposium (Workshop 7) at the 2004 International Continence Society meeting in Paris was to elucidate different mechanisms of urothelial cell pathology, explore their impact on bladder function and discuss novel therapeutic interventions.

RESULTS

The topics included 1) urothelial structure and function, 2) the role of adenosine triphosphate in urothelial signaling and cystitis, 3) lamina propria myofibroblasts and purinergic receptors, 4) antiproliferative factor involvement in interstitial cystitis, 5) the urothelium as a reservoir for bacterial infections, 6) radiation cystitis, nitric oxide and gene therapy, and 7) intravesical treatments.

DISCUSSION

It was agreed that the urothelium can no longer be regarded merely as a passive barrier separating urine from the underlying tissues. The epithelial cells of the urothelium form part of an integrated network that also includes afferent and possibly efferent nerves, and suburothelial myofibroblasts. It has a central role in several functions, including bladder wall sensation, local blood flow modulation, pathogen removal and active barrier provision. These functions are achieved through several autocrine and paracrine pathways that involve transmitter release from the urothelium and its ability to integrate incoming signals through its battery of membrane receptors. Several pathological processes were discussed using this knowledge, including the role of small glycoproteins released during interstitial cystitis, the molecular basis of radiation induced urothelial damage, the origin of recurrent urinary tract infections and the mode of action of potential intravesical treatments for overactive bladder.

CONCLUSIONS

Overall it was concluded that the urothelium has a key role in regulating lower urinary tract physiology and pathology.

Guidelines for the control and prevention of meticillin-resistant Staphylococcus aureus (MRSA) in healthcare facilities

Meticillin-resistant Staphylococcus aureus (MRSA) remains endemic in many UK hospitals. Specific guidelines for control and prevention are justified because MRSA causes serious illness and results in significant additional healthcare costs. Guidelines were drafted by a multi-disciplinary group and these have been finalised following extensive consultation. The recommendations have been graded according to the strength of evidence. Surveillance of MRSA should be undertaken in a systematic way and should be fed back routinely to healthcare staff. The inappropriate or unnecessary use of antibiotics should be avoided, and this will also reduce the likelihood of the emergence and spread of strains with reduced susceptibility to glycopeptides, i.e. vancomycin-intermediate S. aureus/glycopeptide-intermediate S. aureus (VISA/GISA) and vancomycin-resistant S. aureus (VRSA). Screening for MRSA carriage in selected patients and clinical areas should be performed according to locally agreed criteria based upon assessment of the risks and consequences of transmission and infection. Nasal and skin decolonization should be considered in certain categories of patients. The general principles of infection control should be adopted for patients with MRSA, including patient isolation and the appropriate cleaning and decontamination of clinical areas. Inadequate staffing, especially amongst nurses, contributes to the increased prevalence of MRSA. Laboratories should notify the relevant national authorities if VISA/GISA or VRSA isolates are identified.

Clinician-led surgical site infection surveillance of orthopaedic procedures: a UK multi-centre pilot study

The UK Department of Health established the Healthcare-associated Infection (HAI) Surveillance Steering Group in 2000 to develop a strategy for implementing a national programme for HAI surveillance in National Health Service trusts. A subgroup of this committee examined the surveillance of surgical site infections following orthopaedic surgery. This group oversaw a pilot scheme that was set up in 12 hospitals around the UK to explore the feasibility of implementing a system of surveillance that engaged clinical staff in its operation, provided a process for continuous data collection and could be maintained as part of routine hospital operation over time. A minimum data set was established by the subgroup, and Centers for Disease Control and Prevention (CDC) definitions of infection were used. By March 2003, the surveillance had been undertaken continuously in 11 sites for one to two years, depending on the date of implementation. Only one hospital had ceased data collection. The information was collected mainly by clinical staff, with support and co-ordination usually provided by infection control teams. Data on more than 5400 procedures were available for analysis for four core procedures: arthroplasty of the hip and knee; hemi-arthroplasty of the hip; and internal fixation of trochanteric fractures of the femur. The data set permitted the calculation of risk-adjusted rates, allowing comparisons between hospitals and within a hospital over time. The methodology enhanced clinical ownership of the surveillance process, re-inforced infection control as the responsibility of all staff, and provided timely feedback and local data analysis. The use of CDC definitions permitted international comparisons of the data.

Local anesthesia prior to the insertion of peripherally inserted central catheters

Using a randomized, controlled study, the investigators evaluated and compared the effects of local anesthesia versus no anesthesia on pain associated with peripherally inserted central catheter (PICC) insertion. A sample of 42 subjects was selected and divided into three groups. Group 1 received EMLA cream. Group 2 received buffered lidocaine. Group 3 (the control group) did not receive a local anesthetic. The short form of the McGill Pain Questionnaire was used to measure pain quality and intensity. A numerical Visual Analogue Scale accompanied the questionnaire and measured overall pain intensity. Results showed that buffered lidocaine was statistically superior to EMLA cream or no anesthetic in relieving pain associated with PICC insertion.

For love or money? An exploratory study of why injecting drug users participate in research

AIMS

To examine injecting drug user (IDU) motivations as research participants.

DESIGN

Convenience sampling facilitated by recruitment notices distributed through needle and syringe programmes (NSPs), and snowballing within peer networks.

SETTING

NSPs in six suburbs throughout the Melbourne metropolitan area.

PARTICIPANTS

One hundred and fifty-four current IDUs. The mean age was 28 years, 62% were male, and 80% nominated heroin as preferred drug.

MEASUREMENTS

Interviewer-administered survey including questions about socio-demographics, drug use and main reasons for participating in research.

FINDINGS

IDU research participation reasons were consistent with motivational themes such as economic gain (46%), expression of citizenship (38%), altruism (19%), personal satisfaction (17%), drug user activism (16%) and seeking information or assistance (5%). Most respondents (58%) cited reasons where the primary beneficiaries of participation were other individuals or groups (citizenship, altruism, drug user activism) or both self and others.

CONCLUSIONS

IDU motivations for research involvement appear to be multi-dimensional, rarely motivated by economic gain alone, and not necessarily defined by direct benefits or gains to themselves. These findings are relevant to the question of IDU research payment ethics.

Catheter associated urinary tract infection and encrustation

This paper examines the relationship between urinary pH, infection and urinary catheter encrustation and discusses the current management and problems of catheter associated urinary infection and encrustation.

Establishing safe injecting rooms in Australia: attitudes of injecting drug users

OBJECTIVE

To investigate the attitudes of injecting drug users (IDUs) towards the establishment of safe injecting rooms (SIRs) in Melbourne, Australia.

METHODS

Multi-site convenience sampling at Needle and Syringe Exchange Programs (NSEPs) within six Melbourne suburbs. Four hundred current IDUs were recruited directly through NSEP and participant snowballing. Respondents completed either a semi-structured interview, anonymous self-report questionnaire, face-to-face interview or participated in a focus group. Participants were asked to report on their knowledge and attitudes about SIR, their experiences and concerns as participants of street-based illicit drug markets, and their willingness to use SIRs if established.

RESULTS

Participants (91%) were knowledgeable about the SIR issue and thought such a strategy had potential to address both personal and wider community harms associated with public injecting. Most (77%) indicated they would be willing to use a SIR if established in Melbourne. Gender, lifetime non-fatal overdose episodes and frequency of heroin use were all significantly related to a person's willingness to use SIRs. A significant number also reported a preference for injecting at their own place of residence due to concerns regarding privacy, safety and police presence within street-based market places.

CONCLUSIONS

This study has identified a number of important issues relating to the likely demand and uptake of SIRs that should be addressed when considering the feasibility of establishing SIRs within Australia.

An outbreak of methicillin-resistant staphylococcus aureus (MRSA) in a dermatology day-care unit

We describe an outbreak of methicillin-resistant Staphylococcus aureus (MRSA) in a dermatology day-care unit and the methods used to determine the mechanism of spread and control it. The epidemic strain had a characteristic sensitivity pattern and was typeable with phages 29, 80, 95, 47, 54 and 77, which was of considerable value in interpreting the epidemiological data. The method of spread was studied by examination of the medical and nursing records of patients who had acquired MRSA (to determine which members of staff they had encountered and which other MRSA-positive patients had been present in the department at the same time) and by the microbiological screening of all patients and staff. However, screening of all staff by nasal swabbing failed to identify carriage of the epidemic strain, while extensive swabbing of surfaces on the day-care unit also failed to show any evidence of MRSA in the environment. This suggests that the MRSA was most probably spread from patient to patient via the hands of staff, although there was also the possibility of direct transmission from patient to patient. Nine patients acquired the unique strain of MRSA and once acquired it proved difficult to eradicate, although in the majority, the infection did not appear to be clinically significant. However, in two patients MRSA contributed to a fatal outcome: these were the two most elderly patients and were the only two who were receiving systemic corticosteroids. The outbreak was brought under control with rigorous hygienic measures and the decision to discharge all patients with MRSA from the day-care unit. Repeat screening (swabs of nose, axilla and groin) of all day-care unit and in-patients 11 months after the last MRSA case showed no evidence of any residual MRSA infection in the day-care unit.

Effects of interleukins on secretion of luteinizing hormone from ovine pituitary cells

OBJECTIVE

To determine whether cytokines of homologous species might mediate the stimulatory effects of endotoxin on release of luteinizing hormone (LH) from pituitary cells.

SAMPLE POPULATION

Cells from pituitary glands collected from 8- to 14-month-old wethers.

PROCEDURE

Cells from the anterior pituitary gland were cultured in the presence of recombinant ovine or bovine cytokines (interleukin [IL]-1alpha, IL-1beta, and IL-2), tumor necrosis factor-alpha (TNF), and interferon-gamma (IFN-gamma). Luteinizing hormone that was released into the medium was measured. Cells were also cultured with modulators of signal transduction pathways to evaluate the second messenger system used by IL-1 alpha and IL-1beta.

RESULTS

Similar to effects of endotoxin, IL-1alpha and IL-1beta stimulated release of LH. Interleukin 2, TNF, and IFN-gamma did not have a detectable effect on release of LH. Stimulation of LH release by IL-1alpha and IL-1beta required activation of voltage-dependent Ca2+ channels and appeared to involve protein kinase C.

CONCLUSIONS

IL-1alpha and IL-1beta may mediate the direct stimulatory effect of endotoxin on release of LH in vitro. Interleukin 2, TNF, and IFN-gamma do not have a direct effect on release of LH; therefore, they do not mediate this effect of endotoxin.

CLINICAL RELEVANCE

Stressors, including infection, are often associated with reduced fertility. Infection resulting in endotoxin release, production of interleukins, or both, can lead to direct stimulation of LH release from the pituitary gland. Inopportune release of LH via cytokines may interfere with normal pulsatile release of LH, thereby suppressing gonadal function.

Cytokine-mediated growth hormone release from cultured ovine pituitary cells

Previous studies have demonstrated that intravenous lipopolysaccharide (LPS) will increase concentrations of growth hormone (GH). One possible explanation for this may reside in the response of the pituitary to specific cytokines. This study sought to determine the effects of recombinant bovine tumor necrosis factor alpha (TNF), recombinant ovine (ro) interleukin-1alpha (IL-1alpha), roIL-1beta, ro interleukin-2 (IL-2), and ro gamma-interferon (INT) on GH release from cultured sheep pituitary cells. Sheep were sacrificed and pituitary cells cultured in DMEM with 10% fetal bovine serum for 3 days. On day 4, cells were washed and serum-free DMEM added to cells. IL-1alpha and IL-1beta were used at 0.2, 2 and 20 ng/ml and the remaining cytokines at 2, 20 and 200 ng/ml. Neither IL-2 nor INT had effects on basal or on GH-releasing hormone (GRH)-stimulated GH release. TNF inhibited GRH-stimulated GH release (p < 0.05). Both IL-1alpha and IL-1beta stimulated GH release from cultured pituitary cells at all doses tested (p < 0.01). Neither IL-1alpha nor IL-1beta had an effect on GRH-stimulated GH release. IL-1 effects were inhibited by H-89 (p < 0.05; a protein kinase A inhibitor) and by nifedipine (p < 0.05; a calcium channel blocker). Both of these mechanisms are central signal transduction mechanisms mediating GRH-stimulated GH release. IL-1-stimulated GH release is partially inhibited (p < 0.05) by lipoxygenase pathway blockers. Phorbol myristate acetate downregulation of protein kinase C did not alter IL-1-stimulated GH release. IL-1beta increased the content of both GH and GH mRNA in cultured sheep pituitary cells. We conclude that IL-1 produces a strong stimulus to GH release, which is mediated by calcium entry and protein kinase A activation. IL-1 also activates lipoxygenase pathways. This latter pathway as well as calcium entry were shown to mediate LPS stimulation of GH release from cultured pituitary cells. The similarity between IL-1 and LPS signal transduction suggests that LPS may activate pituitary production of IL-1 to produce the stimulus to GH. The lack of inhibitory effects of INT, TNF and IL-2 as opposed to what is seen in the rat may suggest a partial mechanism to explain the different effects of LPS on GH release between sheep and that seen in cattle and rats.

[Ischemic contracture of the forearm and hand. Staging and indications for surgical treatment]

Results of long-term follow up of 66 patients with ischemic contracture of the forearm and hand, all surgically treated in the "Unfallkrankenhaus Hamburg)) between 1961 and 1982, are presented. Whereas ischemic contracture of the forearm flexors resulted mainly from fractures, ischemic contracture of the intrinsic muscles of the hand was most often seen after pressure injuries. All patients in this study presented to us with fully established ischemic contractures. Muscle and nerve damage was retrospectively evaluated according to operative notes, and the degree of damage could be classified into four groups. Most frequently, neurolysis, scar excision and muscle-sliding operations were performed; furthermore, tendon lengthening, tendon transpositions, wrist arthrodesis and nerve grafting were indicated. Results were judged according to twelve separately measured functions, each measurement giving a possible score of three to six points. Muscle-sliding operations result in an improved score regardless of ischemic contracture stage. For a stage 2 contracture, a 20 point improvement can be expected. In stage 1 contracture--presenting with extension deficiency of four or more points--, complete recovery can be expected following a muscle-sliding operation. For isolated muscle injuries, tendon lengthening is recommended. For stage 2 contracture, the transposition of superficial to deep flexor tendons results in the same score as a muscle-sliding operation; however, the transposition procedure should be reserved for special indications. In stage 3 contracture, the muscle-sliding operation is the treatment of choice, with secondary procedures such as tendon transpositions and nerve grafts often being necessary. In stage 4 ischemic contracture, muscle-sliding operations may improve extension deficiency; however, wrist arthrodesis, especially in combination with extensor tendon transpositions, may be beneficial. No experience with free muscle transplantation was made during the study period.

Effect of temperature on calcium exchange in digitonin-treated rat ventricular myocytes

The effect of a change in temperature on net mitochondrial Ca2+ exchange has been investigated in a suspension of adult rat ventricular myocytes. Temperature was varied between 42 degrees C and 15 degrees C. Hypothermia reduced the initial rate of respiration-dependent Ca2+ uptake and reduced the Na+-sensitivity of Ca2+ efflux. The net result of these alterations is that at low temperatures, the Ca2+ level at which a steady-state between mitochondria and sarcoplasm is maintained, will be raised.